1. Technical Field
The present invention is an invention belonging to the life style improving cosmetic in the field of hair maintenance and enrichment. More particularly, it relates to cosmetic compositions having an improved hair care actions such as to prevent hair loss and/or to promote hair growth on the scalp and skin of a mammal.
2. Description of the Related Art
As the aged population is increasing and stress is high in modern society, there are a growing number of people under the threat of hair fall and hair loss. Although medically benign, they can cause tremendous emotional and psychosocial pressure in affected patients and their families. The vast majority of people are thus trying to avoid baldness or alopecia like the plaque, thus an effective treatment is urgently needed.
The Hair Growth Cycle
In mammals, hair does not continuously grow but undergoes a cycle of activity involving alternate periods of growth and rest. Three stages in the hair growth cycle are as follows,
(i) Anagen: an active stage, during which the hair follicle penetrates deep into the dermis with the cells of the bulb dividing rapidly and differentiating to form the hair,
(ii) Catagen: a regressive stage, during which the follicle regresses upwards through the dermis and hair growth ceases,
(iii) Telogen: a resting stage, in which the regressed follicle contains a small secondary germ with an underlying ball of tightly packed dermal papilla cells.
The initiation of a new anagen stage is revealed by rapid proliferation in the germ, expansion of the dermal papilla and elaboration of basement membrane components. The hair cycle is then repeated many times until, as a consequence of the onset of male pattern baldness, most of the hair follicles spend an increasing proportion of their time in the telogen stage, and the hairs produced become finer, shorter, and less visible; this is known as terminal to vellus transformation.
It is generally considered that hair loss is elicited by male hormones, dihydrotesterone (DHT), produced in the hair follicles. DHT may decrease the flow of blood to the hair papilla and hair follicles. It may also cause hypersteatosis, abnormalities on the scalp due to production of reactive oxygen species and/or poor nutrition, etc. Conventional hair tonic compositions have thus been formulated with ingredients having actions in eliminating or alleviating these causes. For example, in order to improve the circulation of blood at the scalp, vasodilators such as swertia herb extract, vitamin E and its derivatives, acetylcholine derivatives, and skin function promoters such as cepharanthine were formulated. Antipyrotics such as shikon extract were also formulated to suppress inflammation of the scalp. Furthermore, to enrich the hair follicles etc., amino acids such as serine and methione, vitamins such as vitamin B 6, etc. are formulated. These are used for the purpose of the prevention of hair loss, the promotion of hair growth, etc.
Two medical treatments were approved by the U.S. Food and Drug Administration (FDA) for male baldness, finasteride (Johannsson, U.S. Pat. No. 2006/0099251 A1) and minoxidil (Chidsey, U.S. Pat. No. 4,139,619). Finasteride was originally used for the treatment of benigh prostatic hyperplasia (BPH) and subsequently found effective for the treatment of male pattern baldness. Finasteride works by inhibiting the activity of 5-alpha-reductase, the enzyme responsible for the conversion of free testosterone to DHT that may induce the follicular miniaturization (Dallob et al, 1994). Finasteride was now marketed as the brand-name drugs, Propecia, by Merck for the baldness treatment on men but not women. Minoxidil is a vasodilator and was originally used as an oral drug (Loniten) to treat high blood pressure. It was discovered to have the side effect of hair growth and reversing baldness in the 1980s. Upjohn Corporation received FDA approval to market a topical solution that contained 2% minoxidil to be used to treat baldness and hair loss (Rogaine and Regaine). The acting mechanism for minoxidil is unclear, but many speculate that by widening blood vessels, opening potassium channels, and allowing more oxygen, blood and nutrients to the follicle.
Minoxidil-induced hair growth was also suggested mediated by adenosine (Li et al, 2001), and presumably through the A2b adenosine receptor pathways (Iino et al, 2007). Therefore, adenosine was unveiled as another functional treatment of baldness Nevertheless; there is general concern that systemic side-effects that may be derived, particularly following topical application of minoxidil and adenosine. Thus it is generally recognized in the medical literature that the side effects of orally administered minoxidil are very serious, and include fluid retention, tachycardia, dyspnea, gynecomastia, fatigue, nausea and cardiotoxicity. There is also evidence that certain side effects have been experienced following topical application of minoxidil. On the other hand, there is a close association of adenosine in cancer formation. The A(1), A(2A), A(2B) and A(3) G-protein-coupled cell surface adenosine receptors (ARs) are found to be upregulated in various tumor cells and activation of the receptors might promote tumor growth via a range of signaling pathways (Fishman et al, 2009).
While various attempts have been made as explained above, current hair tonics have not necessarily had sufficient hair care actions such as prevention of hair loss and promotion of hair growth in any area of the scalps. For examples, finasteride and minoxidil treatments claimed to work on both the vertex area and the frontal area, but are most successful in only the vertex area. In addition, most baldness treatment takes a long period, such as four to six months, before apparently showing the treatment effect. Possibly, the only means which has met with partial success for growing hair on the bald or balding human head is by transplantation of hair to the bald areas. This is usually a painful operation and is not always successful. Furthermore, it is immediately apparent to the casual observer that the subject has received a hair transplant and it may take many months or even years before hair regrowth, following this operation, assumes an appearance which resembles that of the original naturally growing hair.
Current baldness treatments may lift the gloom, but the wide-spread dissatisfactions indicate they are not enough to propel the hair of a relatively regressive and/or resting status toward an active stage, probably due to the diversity of reasons for hair loss and the complexity of the mechanism of hair growth.
It is therefore desirable to provide a novel hair tonic composition having efficient hair care actions on the most areas of scalps.